I tested one and it does show 0.90x in forward direction and 1 in oposite.(diode test mode)

it the test method acceptable?

The diode is from one LCD monitor power supply board. It does click click...

thanks

 

It tells you that it does not suffer the two most common faults - open circuit and short circuit. It does not tell you that the zener voltage is correct though that would be a rare fault. To test the zener voltage you must run a controlled current through the diode in the reverse direction and compare it with the specification for that diode.

 

actually the value in forward direction is 890.
In oposite "1"

What is the range for good and bad?

 

The actual values you see in the forward direction will depend on your meter (how much current it puts through the diode) and on temperature. The reverse direction should always read over-range on the diode test position.